For instance, the list has drawn comparisons to the annual rich lists put out by Forbes.

And it should—the brains behind the Bloomberg list, Matt Miller, worked at Forbes and was heavily involved in the development of Forbes' yearly lists.

A person familiar with the matter told Business Insider that Miller was the real brains behind the list during his tenure.

Miller was employed at Forbes from 2003 to 2010—in his first two years, he worked as a reporter on the Forbes wealth coverage, and spent the rest of his time as an editor of the group.

"I was very involved in the production [of the Forbes lists] and now I'm here doing something that we think is extremely compelling and not the same," Miller told Business Insider in a phone call today.

Forbes declined to comment on Miller's time at the company.

During his time at Forbes, Miller was considered by many to be a rising star at the media company, a person familiar with Forbes told Business Insider.

The course of Miller's career traces a path of lost opportunities for Forbes and leads to Miller joining Bloomberg and building a more evolved, real-time list to rival Forbes. Bloomberg's daily index, which changes depending on stock movement and financial/company news, would erase any anticipation for Forbes' yearly lists.

In fact, even the timing of the release of the Billionaires Index seems like a direct challenge to Forbes. According to a Forbes spokesperson, the magazine's list of the World's Richest in 2012 is expected to be published this Wednesday.

The Bloomberg Billionaire Index is barely a day old. So its true value, its effect on Forbes and its status as a Forbes competitor are still unclear. The index also stops at 20 individuals, though Miller has said that expanding the list is one of his highest priorities.

"We're going to continue to grow this—we're not going to stop at 20 people, not at 100, we're going to keep going," Miller said.

A missed opportunity for Forbes

While Miller was working at Forbes, he and Mykolas Rambus—the former head of IT at the company—pitched to Forbes management a way to monetize Forbes Research, the person familiar said. One idea was to create a Forbes-branded consultancy for high net-worth wealth managers, which would leverage the information gathered to create the wealth lists. But Forbes management were reluctant about the idea because they were unwilling to invest in major new projects while the company was struggling financially.

Miller supposedly proposed to raise capital from outside investors to fund his project idea, that way the company would have to take little financial risk. At the time, it was rumored that Miller got investors to commit around $1 million, the person familiar told Business Insider. But Forbes management ultimately rejected Miller's idea.

Shortly after that, Miller left Forbes with Rambus and started Wealth-X, an intelligence service for wealthy individuals—essentially the same idea that Miller was rumored to have pitched to Forbes.